Liquid containers from which liquids are extracted through a hollow needle stuck into a plug using a rubber membrane have been used widely as drip containers for medical use from long ago. In such use, however, the containers are disposable, so that the needle has never been repeatedly stuck in and pulled out. Liquids contained therein have typically been colorless and transparent, thus yielding no big problems even if somewhat leaking therefrom.
For ink cartridges used for printing devices such as printers and the like, there has been a case where a needle for extraction is used while being repeatedly stuck in and pulled out in order to change kinds of ink. Even a small leak of ink will smear thereabout. Hence, there is a need for a plug from which no ink leaks even when a needle is repeatedly stuck in and pulled out.
For solving this problem, there has been a method of press-fitting a rubber plug having a bore greater than that of a plug part into the plug part by using a special device. However, there has been a necessity for a lubricant to be applied at the time of press fitting in addition to a problem of requiring the special device for press fitting. This has led to a problem of complicating a process of cleaning the lubricant.
A spout disclosed in Patent Literature 1 is one for solving the problems mentioned above. In this spout, an elastic body having a slightly smaller outer diameter is inserted into a cylindrical tap, and then a crown part having a protruded pusher pressing the elastic body is brought into contact with the elastic body under pressure, so as to apply a pressure to the elastic body.
In the spout disclosed in Patent Literature 1, it has been necessary for the crown part to be attached such that the protruded pusher projects from the outside of a hole provided in the cylindrical tap to the elastic body on the inside. Therefore, the crown part has not been easy to attach.
A spout disclosed in Patent Literature 2 is one for making it easier for the crown part (crown body) to attach. In this spout, a tap is provided with a taper part for slidably guiding the crown body along the outer periphery of the peripheral wall part of the tap and a slit for allowing the crown body to deform elastically.
In the spout disclosed in Patent Literature 2, as a method of applying a pressure to the elastic body, a protrusion provided at a center part of the crown body is pressed axially, so as to widen the elastic body radially. This allows a pressing force to act from the inner periphery of the tap.
Therefore, when the bore of the spout is small, the pressing force may fail to work sufficiently in the elastic body having a small bore, thus allowing a liquid to leak therefrom and so forth.
A spout disclosed in Patent Literature 3 is one for solving this problem. In this spout, the elastic body enclosed in the tap has a form larger than the inner space of the tap. The inner face of the crown body is formed with a slope tilted with respect to the extracting direction so that the elastic body enclosed in the tap comes into contact therewith under pressure throughout the periphery when the crown body is attached to the tap.
The spout disclosed in Patent Literature 3 has solved the problem of leaking by employing a structure which applies a pressure to the elastic body from the whole periphery.